United Nations Secretary-General Ban Ki-moon speaks during a joint news conference with Iraq's Prime Minister Nuri al-Maliki in Baghdad Jan 13, 2014. [Photo/Agencies]

UNITED NATIONS - The UN secretary-general has withdrawn his invitation to Iran to join this week's Syria peace talks, saying he is "deeply disappointed" by Iran's statements Monday.

A spokesman for Ban Ki-moon announced the withdrawal less than 24 hours after Ban surprised the US and others by saying he had invited Syria's closest regional ally.

The withdrawn invitation came shortly after Iran's UN ambassador declared the Islamic Republic wouldn't join the Syria talks if required to accept 2012 Geneva roadmap.

A spokesman for Ban, Martin Nesirky, says senior Iranian officials had assured Ban that Iran understood the terms of his invitation.